LUMBAR PUNCTURE

LUMBAR PUNCTURE – Definition, Purpose, Indications, General Instructions, Special Considerations, Equipment Needed, Queckensted’t Test (Lumbar Manometric Test), After Care, Contraindications and Complications

Lumbar puncture (LP) is an invasive procedure; it is carried out by inserting a needle into the lumbar subarachnoid space directly into the intervertebral space in order to withdraw cerebrospinal fluid for diagnostic and therapeutic purposes. The normal range of spinal fluid pressure with the patient in a lateral position is 70 mm to 180 mm of water. Pressure over 200 mm of water is considered abnormal

DEFINITION

Lumbar puncture is a percutaneous puncture entering the spinal column’s subarachnoid space at the vertebral interspaces L3-L4 or L4-L5. A lumbar puncture is performed for cerebrospinal fluid (CSF) pressure measurement, withdrawal of a CSF specimen for analysis and the introduction of contrast media for diagnosis tests

PURPOSE

• To obtain cerebrospinal fluid analysis and to evaluate for signs of infection or hemorrhage
• To measure the intracranial pressure and relive the pressure if it is high
• To administer spinal anesthesia for surgeries
• For intrathecal injection of antibacterial and other drugs
• For evaluation of spinal dynamics for signs of blockage of CSF flow due to tumor or other pathology of spinal cord

INDICATIONS

• To reduce intracranial pressure (ICP) after a spontaneous hemorrhage, by releasing CSF
• To help diagnosis diffuse or disseminated infections of the nervous system or meninges, subarachnoid hemorrhage or demyelinating diseases
• To introduce anesthetic, antibiotics or other therapeutic drugs into the area
• To identify degree of subarachanoid blockage

GENERAL INSTRUCTIONS

• Follow the strict aseptic technique
• Site used for lumbar puncture is between third and fourth and fifth lumbar vertebra in adults and still lower in children
• The position used is side lying with knees drawn to the chin or sitting position with head and knees are flexed
• All the articles used for lumbar puncture should be autoclaved
• The client should be placed near the edge of the bed or table for the convenience of the doctor
• The lumbar puncture needle should be sharp and straight
• The client should empty his bowel and bladder before the procedure
• Use restrain the uni-cooperative clients and children
• The pressure reading taken when the client is relaxed and the fluid level remains fairly constant in the monometer
• Inform the client not to move during the procedure
• Vital signs should be recorded before and after the procedure
• CSF collected should be sent to laboratory immediately along with laboratory request form
• The drug to be injected must be warmed to the body temperature before administration

SPECIAL CONSIDERATIONS

• Do not perform when increased ICP may be caused by a expanding lesion, such as a subdural hematoma after a head injury
• Perform cautiously in client with suspected spinal cord or brain tumor. Procedure may cause fatal cerebellar tonsillar herniation or compression of medulla of the client:

Explain the procedure to the client and relatives to reduce their fear and anxiety

Obtain a written consent for the client or relatives

Instruct the client not to move during the procedure

Help the client to wear a clean and loose garment

EQUIPMENT NEEDED

• A sterile tray containing – LP needles (19-21), sponge holding forceps, 5 ml syringe with needle, two small sterile bowls, three specimen bottles, a spinal sheet, sterile cotton balls, gauze pieces and cotton pads, a three way adapter and monometer tubing, sterile gown, mask and gloves
• A tray containing – Mackintosh and a towel, kidney tray and paper bag, skin antiseptics (spirit, betadine and tincture benzoine), local anesthetic agent xylocaine 1-2 percentage), sterile normal saline, band aid, hand washing articles and screen

Procedure: (done by the doctor and nurse has to assist)

• Explain the procedure
• Position the client
• Wash hands and wear sterile gloves
• Ask the assistant to open the sterile LP set
• Clean the site with spirit and betadine
• Spread the sterile center hole towel
• Puncture the subarachnoid space by accurate identification of L4 and L5 intervertebral spaces
• The initial pressure reading is obtained by measuring the level of the fluid column after it comes to rest
• Collect 2-3 ml of spinal fluid in each of the three test tubes
• After the needle is withdrawn apply pressure at the site for a few minutes
• Apply tincture benzoin seal

QUECKENSTEDT’S TEST (LUMBAR MANOMETRIC TEST)

• This test is done when a spinal subarachnoid block (by tumor, vertebral fracture or dislocation) is suspected
• Pressure may be applied manually by pressing firmly and simultaneously upon the jugular veins on the each side of the neck for a period of 10 seconds or blood pressure cuff may be placed around the client’s neck and inflated to a pressure of 20 mm Hg
• The increase in the pressure caused by the compression is noted
• Then the pressure is released and pressure reading is made at 10 second intervals
• In normal persons, the cerebrospinal fluid pressure rises rapidly in response to compression of the jugular veins and returns quickly to normal when the compression is released
• A slow rise and fall in pressure indicates a partial block due to a lesion compressing the spinal subarachnoid pathways
• If there is no pressure change, a complete block is indicated. This test is done if an intracranial lesion is suspected

AFTER CARE

• Place the client flat for at least 6 hours
• Frequently monitor the neurological vital signs
• Encourage the client to drink plenty of fluids
• Observe puncture site for edema, hematoma and CSF leakage
• Foot end of the bed should elevated
• Replace the articles after washing

CONTRAINDICATIONS

• Cutaneous or osseous infection at the site of lumbar puncture
• When the client has drastically increased LCP, lumbar puncture may result in brainstem compression

COMPLICATIONS

• Post-lumbar puncture headache that becomes severe when the client sits and stands but decreases in a supine position
• Herniation or coning of brain through foramen magnum
• Local pain, edema and hematoma at the punctured site
• Trauma to the tissue at the LP site
• Injury to spinal cord and spinal nerves
• Infection